The show controller t1 command displays the
controller status specific to the controller hardware. This information is
useful for diagnostic tasks performed by technical support personnel. The
Network Processor Module (NPM) or MultiChannel Interface Processor (MIP) can
query the port adapters to determine their current status.

The show controller t1 EXEC command also
provides the following:

Statistics about the T1 link. If you specify a slot and a port
number, statistics for each 15 minute period are displayed.

Use the show controller command to see if
there are alarms or errors displayed by the controller. To see if the framing,
line coding, and slip seconds error counters are increasing, execute the
show controller t1 command repeatedly. Note the
values of the counters for the current interval.

Contact your Service Provider for framing and line coding settings. It
is common to use binary 8-zero substitution (B8ZS) line coding with Extended
Superframe (ESF), and alternate mark inversion (AMI) line coding with Super
Frame (SF). Look for Clock Source is Line Primary in the show
controller t1 output to verify that the clock source is derived
from the network.

A receive (Rx) alarm indication signal (AIS) means there is an alarm
occurring on the line upstream from the equipment that is connected to the
port. The AIS failure is declared when an AIS defect is detected at the input
and still exists after the Loss Of Frame failure is declared (caused by the
unframed nature of the "all-ones" signal). The AIS failure is cleared when the
Loss Of Frame failure is cleared.

To correct Rx AIS errors, complete the following steps:

Check the show controller t1
[slot/port] output to see if the framing
format configured on the port matches the framing format of the line. If not,
change the framing format on the controller to match the line.

To change the framing format, use the framing {SF |
ESF} command in controller configuration mode. For example:

A receive remote alarm indication (RAI) means the far end equipment has
a problem with the signal it is receiving from the upstream equipment.

For SF links, the Far End Alarm failure is declared when bit 6 of all
of the channels has been zero for at least 335 ms. The failure is cleared when
bit 6 of at least one channel is not zero for a period usually less than one
second and always less than five seconds. The Far End Alarm failure is not
declared for SF links when a Loss of Signal is detected.

For ESF links, the Far End Alarm failure is declared if the Yellow
alarm signal pattern occurs in at least seven out of ten contiguous 16-bit
pattern intervals. The failure is cleared if the Yellow alarm signal pattern
does not occur in ten contiguous 16-bit signal pattern intervals.

To correct Rx RAI errors, complete the following steps:

Insert an external loopback cable into the port. To create a
loopback plug:

Use wire cutters to cut a working RJ-45/48 cable that is 5 inches
long with a connector attached.

Strip the wires.

Twist the wires from pins 1 and 4 together.

Twist the wires from pins 2 and 5 together.

The pins on an RJ-45/48 jack are numbered from 1 through 8. With
the metal pins facing toward you, pin 1 is the left-most pin. Following is a
figure of the pin numbers on an RJ-45 jack.

Use the show controller t1 EXEC command
to see if there are any alarms. If you do not see any alarms, then the local
hardware is probably in good condition. In that case, complete the following
steps:

Check the cabling. Ensure that the cable between the interface
port and the T1 Service Provider's equipment or T1 terminal equipment is
connected correctly. Ensure the cable is connected to the correct ports.
Correct the cable connections if necessary.

Check the cable integrity by looking for breaks or other physical
abnormalities in the cable. Ensure the pinouts are set correctly. Replace the
cable if necessary.

Check the settings at the remote end and verify that they match
your port settings.

If the problem persists, contact your service
provider.

Remove the loopback plug and reconnect your T1
line.

Check the cabling.

Power cycle the router.

Connect the T1 line to a different port. Configure the port with
the same settings as the line. If the problem does not persist, then the fault
lies with the port. In this case, complete the following
steps:

A transmit (Tx) remote alarm indication (RAI) at a DS1 interface means
that the interface has a problem with the signal it is receiving from the far
end equipment.

To correct Tx RAI errors, complete the following steps:

Check the settings at the remote end to ensure that they match your
port settings.

A Tx RAI is accompanied by another alarm. This alarm indicates the
problem that the T1 port/card is having with the signal from the far end
equipment. Troubleshoot that condition to resolve the Tx RAI
error.